Flame-proof switch.



W. R. YOUMANS. FLAME PROOF SWITCH.

APPLICATION HLED PBB.26, 1910.

Patented oet. 29,1912.

Hoz und therefore UNITED sTATEs PATENT oEEIoE.

WILLIAM R. YOUMANS, OF COLUMBUS, OHIO, ASSIGNOR TO THE JEFFREY MANUFACTURING COMPANY, A CORPORATION OF OHIO.

FLAME-PROOF SWITCH.

Specification of Letters Patent.

Patented oet'. 29,1912.

Application led February 26, 1910. Serial No. 546,171.

To all 'whom 'it may concern:

Be it known that I, WILLIAM R. YOU- for use in connection with electrical systems andappllancesused 1n mines where danger from explosive gases exists or may arise.

As is well known to those accustomed to the use of electrical appliances, the interruption of a. current produces sparking and sparks or arcs so produced will ignite any inflammable gas that may be present. It becomes necessary to guard against any possible arcing or sparking in the use of electrical machinery, systems or appliances in coal mines'or in'any other mines or places where explosive gases may exist or are liable to form. In the operation of electric drills or electric cutters or other electrically driven mining machines -or mechanism in coal mines, especial care must be exercised to prevent sparking, particularly at the power switches, and .it is with switches of this kind that the present invention is chieflyh concerned.

The best possible means yfor Iguarding against the evil effects of arcing or sparking on the breaking of circuit is to prevent suchv arcing or sparking, or at least to reduce it to the minimum. and then thoroughly shield the arcing terminals from the resence of the explosive gases. 'This may est be accomplished by inclosing the circuit terminals in a suitable chamber and using in connection therewith a preventive or reducer of arcing or sparking. The means devised for this purpose provide for making and breaking the circuit through the agency of mercury movable into and out of connection with the inclosed terminals, and of covering the mercury by an arc preventing or minimizing liquid such as oil, the device so operating that the oil flows in between the terminals as the mercury recedes. Should, however, an arc then chance to form, it is immediately extinguished by the oil und furthermore it being wholly inclosed from any gases that may surround the switch it can do no harm.

The invention therefore consists in the structure of parts and their combination and association for thepurpose specified substantially as hereinafter set forth and claimed.

In the accompanying drawings which form a part of this specification, Figure 1 represents, in front elevation, a circuit opening and', closing switch designed to accomplish the purpose of this invention; Fig. 2

represents a transverse section through a portion of the device seen in Fig. 1, such sectionbeing taken in the plane indicated by the line 2 2; and Fig. 3 is a similar v1ew with the movable member of the switch thrown down into circuit closing position.

The switch illustrated is of the twojpole type and is designed for use as amine entry switch to which the terminals ofl mining lma-` chine cables may be attached and detached at will. It is intended to be so mounted or so fixed in position that the movable part thereof shall take a verticall or upright posipart must be moved to a horizontal or re-A clining position to close the circuit. This movable part of the switch is indicated at 4. It consists of a box-like receptacle formed of some suitable insulating material and is divided into two compartments or cells 5 and 6. This receptacle is hinged at 7 to a vertical support 8 and isprovided with a handle 9 for moving it from vertical to horizontal posit-ion, A spring clip, as 10, is provided on the ve'rtical support for holding said receptacle in upright position and a similar clip 11 is mounted on the horizontal support 12 for holding the receptacle in re clining position. Springs, as 13, are provided for moving the receptacle to the vertical position when its handle is released from the clip 11.

In each cell of the receptacle 4 and at the ends thereof are located circuit terminals. In cell 5 are the terminals 14 'and 15 ofthe positive side of the circuit and incell 6 are terminals 16 and 17 of the negative side of the circuit. They are also located against that side of the receptacle which is lowermost when the receptacle is in reclining or horizontal position so that the mercury, Hg, inV each. cell may readily connect associated terminals as indicated in F ig. 3. lThese terminals may have their contacting surfaces extended as by ribs or fins as indicated.

`tion when the circuit is open, and that said The, mercury and oil may be put into the cells through stoppered openings as indicated at 1S. Obviously, if a switch is designed for one branch only of a circuit, the receptacle 4,would be made with but one cell, therefore the number of cells in the receptacle 4 will be governed by the number of circuits or branches of circuits to be controlled.

The switch may be coupled to the feeders, as at 19 and 20. To provide for coupling mining machines to the switch, any suitable connectors may `be used and either artthereof fixed at the switch. In the orm illustrated, split fingers, as 21, are fixed in place at the switch, as in the blocks 22, and to these lingers are connected the switch circuits as indicated at 23. The cables leading from the mining machines are then provided with the sockets of the connectors as represented at 24, to be placed upon said fingers. Here is another place where sparking must be guarded against and prevented. The present switch is designed to accomplish this end also. Therefore the Vsockets 24 are provided with collars 25, and on the outer, lower corners of the receptacle 4 are provided lugs or stops 26, which engage with said collars 25 when the sockets are in lace and the switch is in circuit closing position. The sockets cannot be removed' while current is on, nor can they be applied to the fingers while current is on, since lugs 26 will prevent either act so long as the handle 9 is in clip 11.

In the operation of the switch, the circuit breaking position is the vertical or upright position of the part 4, Figs. land 2; the mercury being then at the lower end of the cells andthe terminals 14 and 16 being completely separated from the terminals 15 and 17. The circuit closing position is the horizontal or reclining position of part 4. Then the mercury has spread to the contacts 14 and 16 and completed both branches of the circuit. rl`he switch has also locked the sockets 24 of the mining machine terminals to the switch terminal plugs 21. To remove the terminals of the mining machine rom the switch, as in taking the ma.- chine to another gallery or chamber, the handle 9 of' the part 4 must be released from the clip 11, when the springs 13 will carry said part upward and handle 9 .will enter clip 10. The sockets may then be removed with safety because the circuit is broken. In the breaking of the circuit, as the mercury recedes from the terminals 14 and 1G. the oil flows immediately against them, thereby interposing an insulation between the mercurial contact and said terminals, and instantly extinguishing any arc that. might possibly form.

Though the invention has been described with specific reference to mines, it is applicable wherever arcing orsparking is to be rendered innocuous at switch terminals and prevented at the connectors or binding posts of the switch.

The invention claimed is 1. In an elect-ric switch, the combination with a swinging part for effecting the opening and closing of the circuit through the switch, of connector fingers at the switch, terminal sockets fitted to said fingers and provided with exterior collars, said movable part of the switch being provided with lugs for en aging said collars to prevent separa- 'tion o the connectors when the switch is in circuit-closing position, means for holding said movable part of the switch in circuitclosing position, and springs for throwing said`movable part into' circuit-breaking position upon its release from said holding means, thereby insuring the breaking of the circuit by the switch' before the connectors can be separated.

2. In an electric switch, the combination of a movably mounted flame proof casing, conductor wires leadin to the interior of the casing, an automatically acting circuit making and breaking means inside of the casing, connection between the said conductor wires being broken when the casing is in one position and established when the casing is in another position, a stationary conductor terminal to which one of the said ductor terminal adapted to engage the stationary conductor terminal, and a lug on the said casing for holding the movable terminal in engagement with the stationary terminal when the casing is in position to cause connection to be established between the conductor wires.

3. In an electric switch, the combination of a movably mounted casing, electrical contacts within the casing and separated from each other, conductor wires connected respectively with the said contacts, mercury within the casing serving to electrically connect the contacts when the casing is 1n one position, the contacts being normally insulated from each other, a stationary conductor terminal connected with one of the said conductor wires, a movable conductor terminal adapted to engage the said stationary terminal, and a lug on the casing adapted to engage the movable terminal to lock it in engagement with the stationary terminal when the casing is in position to cause the mercury to establish connection between the contacts` In an electric switch, the combination ofa pivotally mounted element, two conductor wires, circuit making and breaking means serving to make electrical connection between the wires when the element is in one position and to break the connection when the element is in another position, a

conductor wires is connected, a movable constationary terminal connected With one .of

the Wires and extending in a. direction parallel with the said element when the latter is in the vposition in which electrical connection is established between the wires, and a, movable conductor terminal adapted to telescopicalfly engage the stationary terminal and having a pai-tuin position to be engaged bythe pivotally mounted element` to hold the terminals in engagement with each other when the said element is in position for the. establishment'of the electrical connection. e

In testimony whereof I ax my signature, in presence of two witnesses.

WM. R. YOUMANS.

Witnesses:

ROBERT R. DUNLOP. N. D. LEVIN. 

